Open trough rain gutters collect debris that falls on the roof and washes down with the rain water. Systems to shield the rain gutter from debris include screens over the open trough and reverse-curve shields. The screens have a tendency to clog with small debris, blocking the rain water from entering the rain gutter.
Reverse-curve shields or hoods generally have a sloped planar section that extends over the rain gutter and a coextensive curved section that first curves forwardly and downwardly over the front of the rain gutter and then curves downwardly and inwardly. Rain water, through liquid adhesion principles, follows the curved section to the lower edge of the shield and falls from this lower edge into the rain gutter. Debris washed down by the rain water falls off at the forward extent of the curved section of the shield and drops to the ground.
Known reverse-curve shields can generally be divided into two types. In a first type, the rear of the shield is integrated into the roof, typically by sliding the rear edge of the shield under the lower, forward edge of the roof covering. Reverse-curve shields typically require a certain amount of vertical spacing above the rain gutter. Open top rain gutters are generally mounted as high as possible on the eave, adjacent to the lower edge of the roof. When a reverse-curve shield is added over an open top rain gutter, the required vertical spacing of the shield above the rain gutter can result in the rear edge of the shield being higher than the roof edge. In order to achieve an appropriate geometric configuration of the shield relative to the rain gutter for correct functionality, this first type of reverse-curve shield is typically used when a reverse-curve shield is added over an existing open top rain gutter.
In the second type of reverse-curve shield, the shield mounts only over the rain gutter, independent of the roof. This second type of reverse-curve shield is mounted with specialized fastening clips and typically mounted with the rain gutter as part of an integrated system. When positioned correctly, the shield is located slightly below the roof edge and completely above both the front edge and back edge of the rain gutter. This type of positioning often leaves the back edge of the gutter located well below the existing flashing with the fascia behind the gutter exposed and susceptible to leakage behind the gutter.
Seams or joints in a rain gutter can leak. Seamless rain gutters, with a single seamless section of rain gutter along each straight section of guttered eave, reduce the possibility of leakage and are preferable over rain gutters with joints or seams along straight sections of rain gutter. In many known rain gutters, including many seamless rain gutters, the fasteners that attach the rain gutter to the eave, pierce the rain gutter. Differential thermal expansion between the rain gutter and eave can generate stress on these fasteners, creating a possibility of failure. A mounting system for a rain gutter that allows the rain gutter and shield to independently expand relative to the eave is desirable.